Daikin 668375401 User Manual

Package Contents/Tools Required
Package includes: Thermostatonbase,thermostatcover,wiringlabels,screwsandwallanchors,
Installation,OperationandApplicationGuide
Tools required for installation:Drillwith3/16”bit,hammer,screwdriver
Important Safety Information
WARNING! :Always turn off power at the main power supply before installing, cleaning, or
removing thermostat.
• Thisthermostatisfor24VAC/VDCapplicationsonly;donotuseonvoltagesover30VAC/VDC
• Donotshortacrossterminalsofsystemcontroltotestoperation;thiswilldamageyourthermostat
andvoidyourwarranty
• Allwiringmustconformtolocalandnationalelectricalandbuildingcodes
• Usethisthermostatonlyasdescribedinthismanual
Specifications
Electrical rating: •24VAC/VDC(18-30VAC/VDC)
 •1ampmaximumperterminal
 •4ampmaximumtotalload
Temperature control range: 45°Fto90°F(7°Cto32°C)Accuracy:±1°F(±0.5°C)
System congurations:2-stageheat,2-stagecool
Timing:
BacklightOperation: 13secondsaftermodechangeorbuttonpress
Terminations:-C,+R,W1,Y1,W2,Y2,G,O,S1,S2
To Remove Existing Thermostat
ELECTRICAL SHOCK HAZARD –Turn off power at the main service panel by removing
the fuse or switching the appropriate circuit breaker to the OFF position before removing the
existing thermostat.
1. Turnoffpowertotheheatingandcoolingsystembyremovingthefuseorswitchingtheappropriate
circuitbreakeroff.
2. Removecoverofoldthermostat.Thisshouldexposethewires.
3. Labeltheexistingwireswiththeenclosedwirelabelsbeforeremovingwires.
4. Afterlabelingwires,removewiresfromwireterminals.
5. Removeexistingthermostatbasefromwall.
6. Refertothefollowingsectionforinstructionsonhowtoinstallthisthermostat.
To Install Thermostat
ELECTRICAL SHOCK HAZARD –Turn off power at the main service panel by removing
the fuse or switching the appropriate circuit breaker to the OFF position before removing the
existing thermostat.
 IMPORTANT:Thermostat installation must conform to local and national building and
electrical codes and ordinances.
Note: Mountthethermostataboutvefeetabovetheoor.Donotmountthethermostat
onanoutsidewall,indirectsunlight,behindadoor,orinanareaaffectedbyavent
orduct.
1. Turnoffpowertotheheatingandcoolingsystembyremovingthefuseorswitchingtheappropriate
circuitbreakeroff.
2. Toremovecover,insertandtwistacoinorscrewdriverintheslotsonthesidesofthethermostat.
3. Putthermostatbaseagainstthewallwhereyouplantomountit(Besurewireswillfeedthrough
thewireopeninginthebaseofthethermostat).
4. Marktheplacementofthemountingholes.
5. Setthermostatbaseandcoverawayfromworkingarea.
6. Usinga3/16”drillbit,drillholesintheplacesyouhavemarkedformounting.
7. Useahammertotapsuppliedanchorsinmountingholes.
8. Alignthermostatbasewithmountingholesandfeedthecontrolwiresthroughwireopening.
9. Usesuppliedscrewstomountthermostatbasetowall.
10. Insertstripped,labeledwiresinmatchingwireterminals.See“WiringDiagrams”sectionofthis
manual.
 CAUTION! : Besureexposedportionofwiresdoesnottouchotherwires.
11. Tightenscrewsonterminalblock.Gentlytugwiretobesureofproperconnection.Doublecheck
thateachwireisconnectedtotheproperterminal.
12. Sealholeforwiresbehindthermostatwithnon-ammableinsulationorputty.
13. Replacecoveronthermostatbysnappingitinplace.
14. Turnonpowertothesystematthemainservicepanel.
15. Testthermostatoperationasdescribedin“TestingtheThermostat”.
Terminal Designator Descriptions
Parts Diagram
R12
W1
Y1 W2 O
S1
S2
668375401
Y2
BacklitDisplay
Reset
CongurationSwitches ModeSwitch FanSwitch
Configuration Mode
ThecongurationmodeisusedtosettheDaikinAuto-changeoverElectronicThermostattomatch
yourheating/coolingsystem. ToconguretheDaikin Auto-changeoverElectronicThermostat ,perform
thefollowingsteps:
1. Removethecoverofthethermostatbygentlypullingononeofthecorners.
2. S imultaneouslyholdtheSW5andSW6buttonsinfor5secondswhiletheDaikin Auto-changeover
ElectronicThermostat isinOFFmode.
3. Pressthe or buttontochangesettingswithineachscreen.
4. Pressthe SW6 buttontoadvancetothenextscreen.
 Note:The SW5 button will return you to the previous screen.
5. Toexitcongurationmode,slidetheModeswitchtoHeatorCool.
FILTER
DIFF
ROOM
SET
REMOTE
Conguration Mode Settings
ThesetupscreensforCongurationModeareasfollows:
1. Heat Pump and Non Heat Pump –Pressthe
or buttontocongureas
heatpump,ornon-heatpumpsystem.Setto“O”forallDaikinWSHP,PTAC,
PTHPandUVunits.
 Pressthe SW6 buttontoadvancetothenextscreen.
FILTER
DIFF
ROOM
SET
REMOTE
2. Setto“g”.
 Pressthe or buttontosetto“g”.
 Pressthebuttontoadvancetothenextscreen.
FILTER
DIFF
ROOM
SET
REMOTE
3. Temperature Scale (F or C) –ChooseFahrenheitorCelsius.
 Pressthe or buttontoselect.
 Pressthe SW6 buttontoadvancetothenextscreen.
 -C–24VAC/VDCcommon
+R–24VAC/VDChot
W1–1ststageheat
Y1–1ststagecool
Remote Sensor Installation (Optional)
Requires Daikin Remote Sensor Part Number 667720401
1. Removecoverfromremotesensorhousing.
2. Selectanappropriatelocationformountingtheremotesensor.
3. Mountremotesensorunitusinghardwareprovided.
4. Installtwostrandshieldedwirebetweenremotesensorandthermostat.Shieldedwiremustbe
used.Donotrunremotesensorwireinconduitwithotherwires.
 • Wire 1shouldrunbetweentheS1terminalonthethermostatandtheS1terminal
ontheremotesensor
 • Wire 2shouldrunbetweentheS2terminalonthethermostatandtheS2terminal
ontheremotesensor
 • ConnecttheshieldingofthewiretotheS2terminalonthethermostat
5. Disablethemainsensor(R12)onthethermostatbycuttingitfromthecircuitboard.
FILTER
DIFF
ROOM
SET
REMOTE
FILTER
DIFF
ROOM
SET
REMOTE
5. 2
nd
StageTemperature Differential (1°Fto6°F)(0.5°Cto3.0°C)
Setthenumberofdegreesbetweenwhenstage1turnsonand
whenstage2turnson.
 Pressthe
or buttontosetdifferentialvalue.
 Pressthe SW6 buttontoadvancetothenextscreen.
FILTER
DIFF
ROOM
SET
REMOTE
FILTER
DIFF
ROOM
SET
REMOTE
4. 1
st
StageTemperature Differential (1°Fto3°F)(0.5°Cto1.5°C)
Setthenumberofdegreesbetweenyour“setpoint”temperature
andyour“turnon”temperature.
 Pressthe
or buttontosetdifferentialvalue.
 Pressthe SW6 buttontoadvancetothenextscreen.
W2–2ndstageheat
Y2–2ndstagecooling
 G–Fan
 O–Override
Wiring Diagram
24 VAC Common
Tenant Override
Fan
Cool 1
Cool 2
Heat 1
Heat 2
Alarm Output
24 VAC
C
O
G
Y1
Y2
W1
W2
A
R
Override (Optional)
Thermostat
Terminals
TB2
MicroTech III Unit Control Board
Low Voltage Terminal Strip (Circuit 1)
Non-Programmable, Auto or Manual Changeover (P/N 668375401)
Two Stage Heat/Two Stage Cool, Night Setback and Override Feature
Note: An additional conductor is required between “O” terminals for the override
feature to work.
Installation, Operation & Application Guide
Version B: 10-15-13
Daikin P/N (668375401)
2 Heat/2 Cool, Auto or Manual Changeover, Hardwired
Non-Programmable Electronic Thermostat
• Configurable
• Two Stage Heat / 2 Stage Cool
Systems
• Backlit Display
• Field Temperature Calibration
• Status Indicator Light
• Relay Outputs (minimum voltage drop
in thermostat)
• Night Set-Back Override
• Reset

Daikin 668375401 Specifications

General

Model Number	668375401
Category	Thermostat
Display	LCD
Power Supply	24VAC
Communication	Wired
Temperature Control Range	50°F to 90°F (10°C to 32°C)
Compatibility	Daikin systems
Weight	120 grams

Summary

Thermostat Components and Specifications

Parts Diagram

Illustrates the physical components of the Daikin thermostat, including the display and switches.

Terminal Designator Descriptions

Defines the function of each terminal on the thermostat for wiring connections.

Wiring Diagram

Provides a visual guide for connecting the thermostat to the HVAC system and optional remote sensor.

Specifications

Details electrical ratings, temperature control range, accuracy, and system compatibility.

Important Safety Information

Crucial warnings and precautions for safe installation and operation of the thermostat.

Package Contents and Tools

Lists items included in the thermostat package and the tools required for installation.

Thermostat Installation Procedures

Removing the Existing Thermostat

Step-by-step instructions for safely disconnecting and removing an old thermostat.

Installing the New Thermostat

Detailed guide for mounting the thermostat base, wiring, and connecting it to the system.

Configuration Mode Settings

Heat Pump and Non Heat Pump Configuration

Sets the thermostat for heat pump or non-heat pump system types.

Fan Operation Setting

Configures the fan behavior, likely for continuous or auto operation.

Temperature Scale Selection

Allows selection between Fahrenheit (°F) and Celsius (°C) for temperature display.

Stage Temperature Differentials

Sets the temperature band for activating first and second stage heating/cooling.

Thermostat Operation Modes and Testing

Operating Modes Overview

Describes the available modes: Off, Cool, Heat, and Auto-changeover.

Override and Reset Functions

Explains how to temporarily override night setback and reset the control board.

Testing Thermostat Functionality

Procedures for testing Cool, Heat, and Fan modes to ensure proper operation.

Troubleshooting Common Issues

Provides solutions for common thermostat problems like no display or incorrect fan operation.